Related Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASTM A1082/A1082M Grade S17700 | 17-7 PH Stainless Steel
Premium spring-grade precipitation hardening steel for aerospace and high-cycle applications
Grade S17700 (UNS S17700) is a semi-austenitic precipitation hardening stainless steel, commonly known as 17-7 PH, containing 17% chromium and 7% nickel with aluminum additions that enable transformation to martensite and subsequent age hardening to achieve exceptional strength levels up to 230 ksi with outstanding fatigue resistance and spring properties. This premium PH grade is extensively used in aerospace applications including bellows, diaphragms, springs, clips, fasteners, and high-performance mechanical components requiring maximum fatigue life, excellent formability in annealed condition, and high strength after heat treatment. S17700 offers superior spring characteristics compared to 17-4 PH with excellent corrosion resistance in atmospheric environments, making it the preferred choice for critical spring applications in aircraft, missiles, and precision instruments where reliability and performance are essential.
ASTM A1082/A1082M Grade S17700 Chemical Composition
| Grades | UNS Designation | Type | C | Mn | P | S | Si | Cr | Ni | Mo | N | Other ElementsB |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ASTM A1082/A1082M Precipitation Hardening Grades | S17700 | 631 | 0.09 | 1.00 | 0.040 | 0.030 | 1.00 | 16.0-18.0 | 6.5-7.7 | . . . | . . . | Al 0.75-1.50 |
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ASTM A1082/A1082M Grade S17700 Solution Treatment
| UNS Designation | Type | Rockwell, max | Brinell max |
|---|---|---|---|
| S17700 | 631 | 98 HRB | 229 |
ASTM A1082/A1082M Grade S17700 Age Hardening Treatment
| Type | Condition | Suggested Hardening and/or Aging Temperatures, Time at Temperature, and Quench Media °F [°C] | Tensile Strength ksi [MPA] | Yield Strength ksi [MPA] | Elongation in 2" [50 mm] or 4D % | Reduction of Area, % | Rockwell, HRC | Brinell |
|---|---|---|---|---|---|---|---|---|
| 631 | RH950 | 1750 [955] for 10 min. to 1 h, rapidly cool to room temperature. Cool within 24 hrs. to -100 ± 10 [-75 ± 5], hold 8 hrs. min. Warm in air to room temperature. Heat to 950 [510] hold 1 h, air cool. | 185 [1280] | 150 [1030] | 6 | 10 | 41 | 388 |
| 631 | Th4050 | 1400 [760] for 90 min. Cool to 55 ± 5 [15 ± 3] within 1 h, hold 1/2 h min., heat to 1050 [565], hold for 90 min., air cool | 170 [1170] | 140 [965] | 6 | 25 | 38 | 352 |
ASTM A1082/A1082M Markings
| UNS Designation | Type | Condition | Grade Symbol |
|---|---|---|---|
| S17700 | 631 | . . . | TB 177 |
| S17700 | 631 | RH95 | TB 177A |
| S17700 | 631 | Th4050 | TB 177B |
Frequently Asked Questions
What is 17-7 PH (S17700)?
17-7 PH (S17700) is a stainless steel grade covered under ASTM A1082/A1082M for high-strength bolting in special-purpose applications such as pressure vessels. UNS designation S17700. Available as bolts, studs, screws and nuts manufactured by TorqBolt for global oil/gas/nuclear/power/marine sectors.
What are the mechanical properties of 17-7 PH (S17700) per ASTM A1082?
Mechanical property requirements for S17700 are defined in ASTM A1082 Table 2 (PH grade solution treatment) or Table 4 (duplex annealed condition). Properties vary by treatment condition - refer to the bolting specification for the H-condition (PH) or annealed yield/tensile/elongation/hardness requirements applicable to your order.
Is 17-7 PH (S17700) suitable for sour service (NACE MR0175)?
Refer to NACE MR0175 / ISO 15156 Tables A.16-A.19. Most A1082 duplex grades are permitted at ≤28 HRC; PH grades require condition-specific qualification (typically H1150 for 17-4 PH at 28 HRC). TorqBolt supplies sour-service certified product on request with full PMI + hardness traceability.
What ASME / ISO dimensional standards can 17-7 PH (S17700) be supplied to?
This grade is available across the full ASME and ISO bolting dimensional standards covered on this site - ASME B18.2.1 (hex bolts, hex cap screws, lag screws), B18.2.2 (hex nuts, square nuts, lock nuts), B18.3 (socket head cap screws), B18.31.2 (clamping studs), B16.5 (flange stud bolts), ISO 4032 / 4033 / 4035 (metric nuts), and metric B18.2.3.xM / B18.2.4.xM series.
References & Standards
- ASTM A1082 / A1082M - Standard Specification for High-Strength Precipitation-Hardening and Duplex Stainless Steel Bolting for Special-Purpose Applications (current edition 2016, active)
- ASTM A962 / A962M - General Requirements for Special-Purpose Bolting Materials
- ASTM A370 - Mechanical Testing of Steel Products
- NACE MR0175 / ISO 15156 - Sour-service hardness limits for petroleum & natural gas industries
- ASME B18 series - Dimensional standards for bolts, screws, nuts, studs
- ISO 4032 / 4033 / 4035 - Metric hexagon nut dimensional standards
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